climate change 4 Flashcards
the water cycle and climate change (14 cards)
water change key aspects
Evaporation, condensation, precipitation
run-off, snow, ocean circulation, permafrost, groundwater etc
energy is provided by the sun, concentrated to equator
movement of gases and wind carry water through the system
greenhouse effect traps the energy from the sun as radiation
effect of GHG on water cycle
GHG effect in solar energy
inc evaporation
change in water cycle impacts whole ecosystem
earth has warmed close to 2 degrees but not the same on the whole globe (poles more)
uneven energy distribution influences global energy transfer cycles
vapour pressure
high temp (high energy) higher vapour pressure
number of particles transitioning into vapour is vapour pressure
vapour pressure deficit (VPD)
vapour pressure difference is how much energy is needed for the atmosphere to become saturated
same relative humidity at a lower temperature is a lower VPD
higher vapour pressure deficit means drier
global changes in VPD
VPD is increasing in some areas and lower in others
because some places have more water in the air than they used to
quantity of water produced in rain has increased because the atmosphere can hold more water (bc warming)
average global temp of 15 degrees and humidity of 40%
planet is dried due to more capacity for water
effect of climate change on ocean process in water cycle
since 2000 water evaporated from the ocean has decreased
more water vapour in atmosphere slowing evaporation
most places have more evaporation that precipitation, some oceans have more precipitation than evaporation
shifting patterns globally
if there is more demand than ppt you get a desert, Australia is being desertified
global trends in ppt due to climate change
average ppt inc in poles, equator and some deserts
most of the planet is experiencing less precipitation
average demand (evapotranspiration) will increase, not enough water
impact of changing ppt trends
less snow, more water per event
large quantities of water when ppt occurs causes run off because soil is saturated
different soils have different levels of water infiltration
e.g. sandy soil lets water infiltrate faster than clay, causing run-off in clay conditions
sand becoming saturated fast could cause the soil to move with water
ecosystem is adapted to a specific quantity of rain so it is damaging
flooding
effect of climate change on evapotranspiration
less water in natural reservoirs
more evaporative demand
causes less water in snow, soil moisture and groundwater
also less snow
higher temp at higher altitudes
effect of climate change on groundwater storage
ground water storage shrinks due to increased run-off and decreased percolation
increased demand from plants and other water causes less water to remain stored
effect of climate change on drought
agricultural drought
water supply drought (hydrological drought)
inc frequency of drought, not enough time for ecosystem to respond or recover
effect of climate change on extreme heat
more days are too hot to be safe for humans
also too hot and too dry for plants
high heat increases evaporative demand (VPD)
reduces global biomass because plants dry
increased VPD increases dryness
impact of climate change on food security
maize production is heavily impacted
wheat will perform better because it is grown in temperature countries
maize has much higher caloric productivity compared to space needed to grow than wheat
water is low in spring and summer when it is most used for irrigation
not enough water over winter to fill water supplies e.g. reservoirs
impact of climate change on safety
more intense and frequent weather events
lower structural safety of buildings
